Rod Reducer Apparatus And Method For Spinal Corrective Surgery

ABSTRACT

Spinal rod reduction apparatuses, systems, and methods are provided. In various examples, a rod reduction apparatus includes a first threaded member including an engagement feature configured to selectively anchor the first threaded member to the implantable screw assembly. A second threaded member is configured to threadably engage with the first threaded member. The second threaded member is axially movable with respect to the first threaded member with rotation of the second threaded member. A spinal rod urging member is axially movable with the second threaded member. The urging member includes a bearing surface that is configured to selectively abut the spinal rod and selectively urge the spinal rod toward the implantable screw assembly with rotation of the second threaded member in a first rotational direction.

CLAIM OF PRIORITY

This application is a divisional of U.S. patent application Ser. No.14/854,424, filed Sep. 15, 2015, which is a divisional of U.S. patentapplication Ser. No. 13/139,373, filed Feb. 9, 2012, which is a NationalStage of International Application No. PCT/US2009/006433, filed Dec. 8,2009, which claims the benefit of U.S. Provisional Application No.61/138,392, filed Dec. 17, 2008, the disclosures of all of which areincorporated herein by reference in their entireties for all purposes.

TECHNICAL FIELD

This patent document pertains generally to orthopedics. Moreparticularly, but not by way of limitation, this patent documentpertains to an apparatus and method for spinal deformity correction.

BACKGROUND

Several techniques exist in the field of spinal surgery for reducing aspinal rod into a posterior pedicle screw. The primary techniqueutilizes a separate rod reduction instrument that couples to the head ofthe screw after the screw is inserted and the rod is placed, such asrocker forks or ratchet style instruments, which are designed to reducethe rod one level at a time, i.e., to each pedicle screw separately.Such segmental reduction techniques may produce large axial loads on thepedicle screws.

Alternatively, a rod can be conformed to a specific deformity and thenseated within an implanted pedicle screw. Once seated, the deformity canbe corrected by bending the rod in situ. This technique may betime-consuming and places stresses and strains on the rod prior toimplantation.

Certain rod reduction techniques utilize specialty reduction pediclescrews that include integrated upwardly extending tabs that can be usedto reduce the rod gradually over the entire length of a deformity. Oncethe rod reduction is completed, the extended tabs are broken off Thistechnique, however, is typically limited to the reduction screw only andcan cause the implant to be expensive.

OVERVIEW

The present inventors have recognized, among other things, that stressesand strains to pedicle screws and/or spinal rods present problems duringspinal rod reduction procedures. The present inventors have furtherrecognized that there exists an unmet need for a streamlined, externallymounted mini-reduction instrument that can be used on any hook or screwtype, including monoaxial, polyaxial, and sagittal screws, and can bereused, modified, or removed as necessary at any time during the entirecourse of the spinal corrective procedure.

This patent document describes, among other things, apparatuses,systems, and methods for spinal rod reduction. In various examples, arod reduction apparatus includes a first threaded member including anengagement feature configured to selectively anchor the first threadedmember to the implantable screw assembly. A second threaded member isconfigured to threadably engage with the first threaded member. Thesecond threaded member is axially movable with respect to the firstthreaded member with rotation of the second threaded member. A spinalrod urging member is axially movable with the second threaded member.The urging member includes a bearing surface that is configured toselectively abut the spinal rod and selectively urge the spinal rodtoward the implantable screw assembly with rotation of the secondthreaded member in a first rotational direction.

In Example 1, an apparatus is configured to selectively engage with aspinal rod and an implantable screw assembly. The apparatus comprises afirst threaded member including first threads around at least a portionof an outer surface of the first threaded member. The first threadedmember includes an engagement feature configured to selectively anchorthe first threaded member to the implantable screw assembly. A secondthreaded member includes second threads around at least a portion of aninner surface of the second threaded member. The second threaded memberis configured to threadably engage with the first threaded member. Thesecond threaded member is axially movable with respect to the firstthreaded member with rotation of the second threaded member. A spinalrod urging member is axially movable with the second threaded member.The urging member includes a bearing surface that is configured toselectively abut the spinal rod and selectively urge the spinal rodtoward the implantable screw assembly with rotation of the secondthreaded member in a first rotational direction.

In Example 2, the apparatus of Example 1 optionally is configured suchthat the engagement feature includes at least one protrusion configuredto mate with a corresponding number of receptacles of the implantablescrew assembly.

In Example 3, the apparatus of one or more of Examples 1-2 optionally isconfigured such that the engagement feature includes a grasping elementconfigured to selectively couple to a proximal end of the implantablescrew assembly.

In Example 4, the apparatus of one or more of Examples 1-3 optionally isconfigured such that the engagement feature is disposed at a distal endof the first threaded member.

In Example 5, the apparatus of one or more of Examples 1-4 optionally isconfigured such that the urging member is coupled to the second threadedmember.

In Example 6, the apparatus of one or more of Examples 1-5 optionally isconfigured such that the first threaded member is substantially tubularand includes a first leg and a second leg, the first and second legsextending substantially axially, wherein distal ends of the first andsecond legs are configured to be selectively radially separable.

In Example 7, the apparatus of Example 6 optionally is configured suchthat the first and second legs are substantially semi-circular in crosssection.

In Example 8, the apparatus of Example 7 optionally is configured suchthat the first and second legs of the first threaded member are heldtogether by the second threaded member threadably engaged around theouter surface of the first threaded member.

In Example 9, the apparatus of Example 8 optionally is configured suchthat the outer surface of the first threaded member includes a portionof decreased diameter configured to allow the first and second legs toselectively radially separate with the first threaded member threadablyengaged with the second threaded member.

In Example 10, the apparatus of one or more of Examples 6-9 optionallyis configured such that the first threaded member includes a gap betweenthe first leg and the second leg, the gap being configured toaccommodate the spinal rod.

In Example 11, the apparatus of Example 10 optionally is configured suchthat the bearing surface of the urging member is disposed at leastpartially within the gap between the first leg and the second leg.

In Example 12, the apparatus of one or more of Examples 1-11 optionallyis configured such that the second threaded member includes a toolengagement portion configured to engage with a tool configured to rotatethe second threaded member with respect to the first thread member.

In Example 13, the apparatus of Example 12 optionally is configured suchthat the tool engagement portion includes a recess including a drivesurface configured to mate with the tool.

In Example 14, the apparatus of one or more of Examples 12-13 optionallyis configured such that the tool engagement portion includes a nutconfigured to mate with the tool.

In Example 15, the apparatus of Example 14 optionally is configured suchthat the nut includes a hex nut.

In Example 16, the apparatus of one or more of Examples 1-15 optionallyis configured such that the spinal rod urging member includes a clawelement including one or more arms, each arm including the bearingsurface configured to selectively abut the spinal rod.

In Example 17, the apparatus of Example 16 optionally is configured suchthat the bearing surface of each arm is disposed at an end of the arm.

In Example 18, the apparatus of one or more of Examples 16-17 optionallyis configured such that the bearing surface includes a rod recess.

In Example 19, the apparatus of one or more of Examples 1-18 optionallyis configured such that the engagement feature of the first threadedmember includes a grasping element configured to couple to an undersideof a head of the implantable screw assembly.

In Example 20, the apparatus of one or more of Examples 1-19 optionallyis configured such that the second threaded member includes a grippingsurface configured to grip during manual rotation of the second threadedmember with respect to the first threaded member.

In Example 21, an method comprises placing at least one rod reduceralong a spinal rod and substantially in alignment with at least onepedicle screw. Placement of the rod reducer along the spinal rodincludes substantially aligning a bearing surface of a spinal rod urgingmember of the rod reducer with the spinal rod. The rod reducer isengaged with the pedicle screw. The rod reducer is incrementallyactuated to gradually reduce the spinal rod into engagement with thepedicle screw. Actuation of the rod reducer causes movement of thebearing surface toward the pedicle screw to urge the spinal rod towardthe pedicle screw. The pedicle screw is engaged with the spinal rod.

In Example 22, the apparatus of Example 21 optionally is configured suchthat engaging the pedicle screw with the spinal rod includes attaching alocking cap to the pedicle screw to retain the spinal rod in engagementwith the pedicle screw.

In Example 23, the apparatus of one or more of Examples 21-22 optionallycomprises removing the rod reducer from the pedicle screw afterengagement of the pedicle screw with the spinal rod.

In Example 24, the apparatus of Example 23 optionally comprises cleaningthe rod reducer for reuse after removal of the rod reducer from thepedicle screw.

In Example 25, the apparatus of one or more of Examples 21-24 optionallyis configured such that placing the at least one rod reducer along thespinal rod includes placing two or more rod reducers along the spinalrod and substantially in alignment with two or more pedicle screws.

In Example 26, the apparatus of one or more of Examples 21-25 optionallycomprises placing the spinal rod along a plurality of pedicle screws.Without using a rod reducer, the spinal rod is engaged to one or morepedicle screws for which no spinal rod reduction is necessary. Using oneor more rod reducers, the spinal rod is engaged to one or more pediclescrews for which spinal rod reduction is necessary.

In Example 27, the apparatus of one or more of Examples 21-26 optionallyis configured such that engaging the rod reducer with the pedicle screwincludes manually engaging the rod reducer with the pedicle screw.

In Example 28, the apparatus of one or more of Examples 21-27 optionallyis configured such that engaging the rod reducer with the pedicle screwincludes engaging the rod reducer with the pedicle screw using a toolconfigured to mate with a tool engagement portion of the rod reducer.

In Example 29, a spinal rod reduction system comprises a spinal rod. Aplurality of pedicle screws is configured to engage with the spinal rod.A plurality of rod reducers each includes a first threaded memberincluding first threads around at least a portion of an outer surface ofthe first threaded member. The first threaded member includes anengagement feature configured to selectively anchor the first threadedmember to the pedicle screw. A second threaded member includes secondthreads around at least a portion of an inner surface of the secondthreaded member. The second threaded member is configured to threadablyengage with the first threaded member. The second threaded member isaxially movable with respect to the first threaded member with rotationof the second threaded member. A spinal rod urging member is axiallymovable with the second threaded member. The urging member includes abearing surface that is configured to selectively abut the spinal rodand selectively urge the spinal rod toward the pedicle screw withrotation of the second threaded member in a first rotational direction.

In Example 30, the system of Example 29 optionally is configured suchthat the rod reducers are configured to engage with the pedicle screwsand the spinal rod at locations where the spinal rod is spaced from thepedicle screws.

In Example 31, the system of one or more of Examples 29-30 optionally isconfigured such that the plurality of rod reducers are configured toincrementally urge the spinal rod toward the plurality of pediclescrews.

In Example 32, the system of one or more of Examples 29-31 optionallycomprises a locking cap configured to engage with the pedicle screw andretain the spinal rod in engagement with the pedicle screw.

In Example 33, the system of one or more of Examples 29-32 optionallycomprises a tool configured to mate with a tool engagement portion ofeach of the rod reducers, the tool being configured to rotate the secondthreaded member with respect to the first thread member.

In Example 34, the system of Example 33 optionally is configured suchthat the tool engagement portion includes a recess including a drivesurface configured to mate with the tool.

In Example 35, the system of one or more of Examples 33-34 optionally isconfigured such that the tool engagement portion includes a nutconfigured to mate with the tool.

In Example 36, a spinal rod reduction assembly comprises one or morepedicle screws engaged with one or more vertebrae. A spinal rod issubstantially aligned with the one or more pedicle screws. At least onerod reducer is removably engaged with at least one pedicle screw at alocation where the spinal rod is spaced by a distance from the pediclescrew. The rod reducer includes a spinal rod urging member axiallymovable with respect to the rod reducer. The urging member includes abearing surface that is configured to selectively abut the spinal rodand selectively urge, with actuation of the rod reducer, the spinal rodtoward the pedicle screw to decrease the distance between the spinal rodand the pedicle screw.

These and other examples, advantages, and features of the present rodreduction appartuses and methods will be set forth in part in thefollowing Detailed Description. As such, this Overview is intended toprovide an overview of subject matter of the present patent document. Itis not intended to provide an exclusive or exhaustive explanation of theinvention. The Detailed Description is included to provide furtherinformation about the present patent document.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like numerals describe similar components throughoutthe several views. Like numerals having different letter suffixesrepresent different instances of similar components. The drawingsillustrate generally, by way of example, but not by way of limitation,various embodiments discussed in the present document.

FIGS. 1A and 1B illustrate a front perspective view and a frontelevational view, respectively, of a miniature rod reducer instrument inaccordance with an embodiment of the present document;

FIGS. 2A, 2B, and 2C illustrate a side elevational view, across-sectional view taken along line 2B-2B of FIG. 2A, and a top planview, respectively, of an outer drive sleeve element of the miniaturerod reducer instrument of FIG. 1;

FIGS. 3A, 3B, and 3C illustrate a front elevational view, a left sideelevational view, and a top plan view, respectively, of a retainingguide ring element of the miniature rod reducer instrument of FIG. 1;

FIGS. 4A, 4B, and 4C illustrate a front elevational view, across-sectional view taken directly into the page of FIG. 4A, and across-sectional view taken along line 4C-4C of FIG. 4A, respectively, ofa threaded tube element of the miniature rod reducer instrument of FIG.1;

FIGS. 5A and 5B illustrate front perspective views of the miniature rodreducer instrument of FIG. 1 coupled to a spinal rod and a pedicle screwassembly in an unreduced and reduced rod configuration, respectively;

FIGS. 6A and 6B illustrate perspective, cross-sectional views takenalong lines 6A-6A and 6B-6B of FIG. 5B of the rod reducer instrument ofFIG. 1;

FIG. 7 illustrates a front perspective view of the rod reducerinstrument of FIG. 1 coupled to a locking cap ratcheting T-handle driverinstrument with a hex drive coupler, a spinal rod, and a pedicle screwassembly;

FIGS. 8A-8D illustrate various perspective views of a miniature rodreducer instrument in accordance with an embodiment of the presentdocument; and

FIGS. 9A-9F illustrate various perspective views of a miniature rodreducer instrument in accordance with an embodiment of the presentdocument.

DETAILED DESCRIPTION

The present inventors have recognized, among other things, that it isdesirable to construct a streamlined, externally mounted mini-reductioninstrument that can be used on any hook or screw type, includingmonoaxial, polyaxial, and sagittal screws, and can be reused, modified,or removed as necessary at any time during the entire course of thespinal corrective procedure.

Certain terminology is used in the following description for convenienceonly and is not limiting. The words “right”, “left”, “lower” and “upper”designate directions in the drawings to which reference is made. Thewords “inwardly” or “distally” and “outwardly” or “proximally” refer todirections toward and away from, respectively, the geometric center ororientation of the instrument assembly and related parts thereof. Thewords, “anterior”, “posterior”, “superior,” “inferior”, “lateral” andrelated words and/or phrases designate preferred positions andorientations in the human body to which reference is made and are notmeant to be limiting. The terminology includes the above-listed words,derivatives thereof and words of similar import.

In reference to FIGS. 1-7, a miniature rod reducer instrument 100 inaccordance with an embodiment of the present invention includes an outerdrive sleeve 110, a retaining guide ring 120, and a threaded tube 130.The rod reducer 100 is selectively engageable with a spinal rod 140 anda pedicle screw assembly 150, which can assume the form of a monoaxialpedicle screw, a sagittal screw, a polyaxial pedicle screw, a hook ornearly any type of screw that includes a head or anchor seat constructedto engage a distal end of the threaded tube 130. The outer drive sleeve110, in an example, includes a proximal end, a distal end, alongitudinal axis between the proximal and distal ends, a cannulatedinterior, a gripping surface 112 disposed on a proximal exterior surfacethat may include a knurled or other traction grip surface, a visibilitywindow 114 that enables viewing and weight reduction, a drive surface116 such as a hex drive disposed interior to the proximal end and aseries of interior threading 118 disposed on an interior surface at thedistal end. The drive surface 116, in an example, is engageable with aratcheting T-handle driver instrument (FIG. 7) with a hex drive coupler160 to impart additional mechanical rotational force to the outer drivesleeve 110 to assist in rod reduction.

In an example, the threaded tube 130 includes a proximal end, a distalend, a longitudinal axis extending between the proximal and distal ends,a cannulated interior, a first leg 132 and a second leg 134. The firstand second legs 132, 134, in an example, are held together by theinterior confines of the outer drive sleeve 110 and the retaining guidering 120. In some examples, the first leg 132 includes an exteriorthreading 136A and the second leg 134 includes an exterior threading136B. The exterior threading 136A, 136B can be a single or multi-leadthread to provide for faster reduction speed. In an example, theexterior threading 136A, 136B is a two start M18×1.5 with an effectivepitch of 3 mm. In some examples, the first leg 132 includes anengagement feature 138A interior to its distal end and the second leg134 includes an engagement feature 138B interior to its distal end. Theengagement features 138A, 138B selectively engage and couple to theexterior surface of a pedicle screw assembly 150. In an example, theengagement features 138A, 138B are comprised of male protrusions thatmate with female receptacles inherent on the exterior surface of thepedicle screw assembly 150. The engagement features 138A, 138B and theircorresponding receptacles, in an example, provide stabilization in allthree axes, as is best shown in FIG. 6A. In an example, the first leg132 includes an exteriorly disposed feature 139A near the proximal endand the second leg 134 includes an exteriorly disposed feature 139B nearthe proximal end. The exteriorly disposed features 139A, 139B, in anexample, are comprised of regions in which the outer diameter of thethreaded tube 130 and the pitch diameter of the exterior threading 136A,136B decrease to allow the first and second arms 132, 134 to splay openslightly at the distal end to enable easy introduction of the rodreducer 100 over the pedicle screw assembly 150 and correspondingengagement of the engagement features 138A, 138B with the receptacles ofthe pedicle screw assembly 150. The first and second arms 132, 134 areconfigured to splay open at the distal end approximately 2.5 degrees inan example.

In an example, the retaining guide ring 120 is disposed around thethreaded tube 130 at the distal end of the outer drive sleeve 110 andincludes first and second upwardly extending arms 122A, 122B, first andsecond outwardly extending tabs 124A, 124B disposed on ends of theupwardly extending arms 122A, 122B, respectively, and a rod recess 126disposed at the distal end of the retaining guide ring 120 thatselectively interfaces with the spinal rod 140.

In an example, the outer drive sleeve 110 is constructed of stainlesssteel, titanium, or other biocompatible surgical grade metal, while theretaining guide ring 120 and threaded tube 130 are constructed of abiocompatible polymer material such as polyetheretherketone (PEEK).However, the drive sleeve 110 is not limited to metallic constructionsand the retaining guide ring 120 and the threaded tube 130 are notlimited to polymeric constructions and each may be constructed of anybiocompatible material that is able to take on the general shape andwithstand the normal operating conditions of the components. Forexample, the retaining guide ring 120 and threaded tube 130 may beconstructed of titanium and the drive sleeve 110 may be constructed ofPEEK.

In operation, and in continuing reference to FIGS. 1-7, a pedicle screwor several pedicle screw assemblies 150 are implanted into the vertebraeof a patient and the rod 140 may be pre-bent for potential deformitycorrection. The spinal rod 140 is loosely placed above the construct ofpedicle screws 150 and attached to the pedicle screws 150 in which noreduction is necessary. The gripping surface 112 of the outer drivesleeve 110 is engaged and rotated with respect to the threaded tube 130using manual rotation and/or the outer drive sleeve 110 may be rotatedusing the ratcheting T-handle driver instrument with a hex drive coupler160 via the drive surface 116. The retaining guide ring 120 surroundsthe features 139A, 139B such that the distal ends of the first andsecond legs 132, 134 splay open. The distal end of the rod reducer 100is placed over the spinal rod 140 and above a pedicle screw assembly 150such that the first and second legs 132, 134 straddle the rod 140 andthe engagement features 138A, 138B surround the correspondingreceptacles on the pedicle screw assembly 150. The outer drive sleeve110 is then rotated manually with respect to the threaded tube 130 viathe gripping surface 112 and/or rotating the ratcheting T-handle driverinstrument with a hex drive coupler 160 with such that the retainingguide ring 120 and the outer drive sleeve 110 travel distally withrespect to the threaded tube 130 via the engagement of the interiorthreading 118 and the first and second exterior threading 136A, 136B,thereby causing the unsplaying of the distal ends of the first andsecond arms 132, 134, engagement of the first and second engagementfeatures 138A, 138B with the receptacles on the pedicle screw 150,engagement of the rod recess 126 to the spinal rod 140, and downwardtranslation of the spinal rod 140 with respect to the first and secondlegs 132, 134. A plurality of rod reducer instruments 100 can beutilized in this manner to gradually reduce the spinal rod 140 into aplurality of pedicle screw assemblies 150 over a plurality of spinallevels. The rod reducers 100, in an example, are slowly andsystematically actuated to avoid overstressing the pedicle screwassemblies 150 and the interface with their corresponding vertebralbodies, which further allows for gradual stressing and stretching ofsoft tissue of the patient's spine while potentially correcting adeformity. The ratcheting T-handle driver instrument with a hex drivecoupler 160 is then uncoupled from the outer drive sleeve 110 andlocking caps, elements which serve to finally secure the spinal rod 140with respect to the pedicle screw assemblies 150, are introduced throughthe rod reducers 100 via a locking cap channel provided by the interiorgeometry of the threaded tube 130. The locking caps can be coupled tothe pedicle screw assemblies 150 using a cap driver instrument (notshown), which can be inserted through the rod reducer 100. The lockingcap driver 160 has an engagement feature for coupling to the lockingcaps and actuating their coupling to the pedicle screw assemblies 150,such as a threaded, star drive, or hex drive engagement feature. Thelocking cap driver 160 may be a ratcheting driver, but is not solimited. In an example, the locking caps are coupled to the pediclescrew assemblies 150 and the locking cap driver 160 is uncoupled fromthe rod reducers 100. The rod reducer(s) 100 are uncoupled from thepedicle screw assemblies 150 by disposing the retaining guide ring 120over the features 139A, 139B such that the distal ends of the arms 132,134 are splayed open and the engagement features 138A, 138B aredisengaged from their corresponding receptacles on the pedicle screwassembly(s) 150. The rod reducer 100 can be cleaned and sterilized forreuse.

In some examples, the rod reducer 100 does not introduce notches or marthe exterior of the spinal rod 140 during its reduction. In addition,the rod reducer 100 of some examples prevents splaying of the upwardlyextending arms that form the rod-receiving channel of the pedicle screwassembly 150.

The rod reducer 100 can be coupled to a pedicle screw assembly 150 priorto or subsequent to the implantation of the pedicle screw 150, accordingto surgeon preference. The rod reducer 100 can further be utilized toaid in de-rotation maneuvers of the spine during surgery.

In an example, and in reference to FIGS. 8A-8D, a rod reducer 200 isprovided that is configured especially for coupling to a monoaxialpedicle screw 250 and reducing a spinal rod 140 thereto. In an example,the rod reducer 200 includes a threaded shaft 210 terminating distallyin a grasping element 220 for coupling to the underside of the distalend of a monoaxial pedicle screw assembly 250. The rod reducer 200further includes a nut 230 configured to interface with the exteriorthreading of the shaft 210 and threadedly translate with respectthereto. A claw element 240 having one or more arms, in an example, iscoupled to the shaft 210 below the nut 230 and the one or more arms, ina further example, have a rod recess 242 for engaging the spinal rod140.

In operation, and in continuing reference to FIGS. 8A-8D, the graspingelement 220 is placed under a monoaxial pedicle screw 250. The clawelement 240 engages the proximal side of the spinal rod and the nut 230is rotated to force the claw element 240 to reduce the rod 140 via therod recess 242 into the monoaxial pedicle screw assembly 250. A lockingcap is coupled to the monoaxial pedicle screw assembly 250 and the rodreducer 200 is decoupled from the monoaxial pedicle screw assembly 250by loosening the nut 230 and disengaging the claw 240 from the spinalrod 140.

In an example, and in reference to FIGS. 9A-9F, a rod reducer 300 isprovided that includes a hex nut 310, a threaded tube 330 having a firstleg 332 and a second leg 334, and a retaining guide ring 320. In anexample, the rod reducer 300 is similar in function and operation to therod reducer 100 with the exception that instead of the outer drivesleeve 110, the hex nut 310 is included and functions in conjunctionwith a hex socket type instrument (not shown) to actuate the rod reducer300. The threaded tube 330 is similar in function and operation to thethreaded tube 130 but incorporates a hinge design at the proximal end tocontrol the splaying of the first and second legs 332, 334.

It will be appreciated by those skilled in the art that changes could bemade to the embodiments described above without departing from the broadinventive concept thereof. It is understood, therefore, that thisinvention is not limited to the particular embodiments disclosed, but itis intended to cover modifications within the spirit and scope of thepresent invention as defined by the present description.

The above Detailed Description includes references to the accompanyingdrawings, which form a part of the Detailed Description. The drawingsshow, by way of illustration, specific embodiments in which theinvention can be practiced. These embodiments are also referred toherein as “examples.” All publications, patents, and patent documentsreferred to in this document are incorporated by reference herein intheir entirety, as though individually incorporated by reference. In theevent of inconsistent usages between this document and those documentsso incorporated by reference, the usage in the incorporated reference(s)should be considered supplementary to that of this document; forirreconcilable inconsistencies, the usage in this document controls.

In this document, the terms “a” or “an” are used, as is common in patentdocuments, to include one or more than one, independent of any otherinstances or usages of “at least one” or “one or more.” In thisdocument, the term “or” is used to refer to a nonexclusive or, such that“A or B” includes “A but not B,” “B but not A,” and “A and B,” unlessotherwise indicated. In the appended claims, the terms “including” and“in which” are used as the plain-English equivalents of the respectiveterms “comprising” and “wherein.” Also, in the following claims, theterms “including” and “comprising” are open-ended, that is, a system,device, article, or process that includes elements in addition to thoselisted after such a term in a claim are still deemed to fall within thescope of that claim. Moreover, in the following claims, the terms“first,” “second,” and “third,” etc. are used merely as labels, and arenot intended to impose numerical requirements on their objects.

The above description is intended to be illustrative, and notrestrictive. For example, the above-described examples (or one or morefeatures thereof) may be used in combination with each other. Otherembodiments can be used, such as by one of ordinary skill in the artupon reviewing the above description. Also, in the above DetailedDescription, various features may be grouped together to streamline thedisclosure. This should not be interpreted as intending that anunclaimed disclosed feature is essential to any claim. Rather, inventivesubject matter may lie in less than all features of a particulardisclosed embodiment. Thus, the following claims are hereby incorporatedinto the Detailed Description, with each claim standing on its own as aseparate embodiment. The scope of the invention should be determinedwith reference to the appended claims, along with the full scope ofequivalents to which such claims are entitled.

The Abstract is provided to allow the reader to quickly ascertain thenature of the technical disclosure. It is submitted with theunderstanding that it will not be used to interpret or limit the scopeor meaning of the claims.

What is claimed is:
 1. A method comprising: placing at least one rodreducer along a spinal rod and substantially in alignment with at leastone pedicle screw, wherein placement of the rod reducer along the spinalrod includes substantially aligning a bearing surface of a spinal rodurging member of the rod reducer with the spinal rod; engaging the rodreducer with the pedicle screw; incrementally actuating the rod reducerto gradually reduce the spinal rod into engagement with the pediclescrew, wherein actuation of the rod reducer causes movement of thebearing surface toward the pedicle screw to urge the spinal rod towardthe pedicle screw; and engaging the pedicle screw with the spinal rod.